Papermaker's forming fabric with twice as many bottom MD yarns as top MD yarns

A papermaker's fabric, comprising top machine direction yarns, top cross machine direction yarns, bottom machine direction yarns, bottom cross machine direction yarns and stitching yarns, the fabric being formed in a plurality of repeating units, each of the repeating units comprising:

• a set of eight top machine direction yarns;
• a set of top cross machine direction yarns interwoven with the set of top machine direction yarns to form a top fabric layer;
• a set of sixteen bottom machine direction yarns;
• a set of bottom cross machine direction yarns interwoven with the set of bottom machine direction yarns to form a bottom fabric layer;
• and
• sets of first and second stitching yarns interwoven with the top and bottom fabric layers;
• wherein the bottom machine direction yarns and the bottom cross machine direction yarns are interwoven in a series of repeat units in which the bottom cross machine direction yarns pass above bottom machine direction yarns to form bottom machine direction knuckles, each bottom machine direction knuckle under a common bottom cross machine direction yarn being separated by seven bottom machine direction yarns.

A triple layer papermaker's fabric, comprising:

• a set of top machine direction yarns;
• a set of top cross machine direction yarns interwoven with the top machine direction yarns to form a top fabric layer;
• a set of bottom machine direction yarns;
• a set of bottom cross machine direction yarns interwoven with the bottom machine direction yarns to form a bottom fabric layer;
• wherein the bottom fabric layer is stitched to the top fabric layer via a set of stitching yarns;
• wherein the top machine direction yarns and the top cross machine direction yarns are interwoven in a series of repeat units and the bottom machine direction yarns and the bottom cross machine direction yarns are interwoven in a series of corresponding repeat units;
• and
• wherein each repeat unit has twice the number of bottom machine direction yarns as the number of top machine direction yarns;
• and
• wherein the set of stitching yarns comprises pairs of first and second stitching yarns positioned between pairs of adjacent top cross machine direction yarns;
• and
• wherein the pairs of first and second stitching yarns are interwoven with the top machine direction yarns and the bottom machine direction such that the top cross machine direction yarns and the first and second stitching yarns form a plain weave pattern with the top machine direction yarns;
• and
• wherein a stitching yarn passes below each of the bottom machine direction yarns and forms a knuckle thereunder.

A triple layer papermaker's fabric, comprising:

• a set of top machine direction yarns;
• a set of top cross machine direction yarns interwoven with the top machine direction yarns to form a top fabric layer;
• a set of bottom machine direction yarns;
• a set of bottom cross machine direction yarns interwoven with the bottom machine direction yarns to form a bottom fabric layer;
• and
• a set of stitching yarn pairs interwoven with the top and bottom fabric layers in a series of repeat units, the set of stitching yarn pairs comprising pairs of first and second stitching yarns positioned between pairs of adjacent top cross machine direction yarns,
• wherein the top machine direction yarns and the top cross machine direction yarns are interwoven in a series of repeat units and the bottom machine direction yarns and the bottom cross machine direction yarns are interwoven in a series of corresponding repeat units;
• and
• further comprising a set of stitching yarn pairs interwoven with the top and bottom fabric layers in a series of repeat units, the set of stitching yarn pairs comprising pairs of first and second stitching yarns positioned between pairs of adjacent top cross machine direction yarns;
• wherein each repeat unit has twice the number of bottom machine direction yarns as the number of top machine direction yarns;
• at least one of the stitching yarn pairs forming a fiber support portion by interweaving with the top machine direction yarns and forming a binding portion by interweaving with the bottom machine direction yarns so that the binding portion of the stitching yarns passes below bottom machine direction yarns to form stitching yarn knuckles;
• at least one other of the stitching yarn pairs being a pair of pseudo stitching yarns that interweave with the top machine direction yarns to form a plain weave pattern without forming a stitching yarn knuckle.